Sweet Leek and Mushroom Open-Topped Pie Recipe

Start by making the filling. Get your biggest frying pan over a high heat and add 1 tbsp of olive oil. Add a third of the mushrooms or enough to cover the base of the pan, season with salt and pepper, and sauté until nicely brown and beginning to crisp at the edges (around 10 minutes.) Transfer to a bowl and keep frying the rest in batches until all the mushrooms are golden, adding 1 tbsp of olive oil after each batch

When all the mushrooms are in the bowl, put the pan back on the heat and add the remaining olive oil. Add the garlic, thyme and leeks, season with a good pinch of salt and pepper and cook on a medium heat for 15 minutes, until buttery and soft. Meanwhile, preheat an oven to 200°C/ fan 180°C/gas mark 5

Next, add the cooked mushrooms back in the pan with the wine or stock and simmer until almost all the liquid has evaporated, another 5–7 minutes. Now add the mustards, parsley and crème fraîche, then take off the heat and allow to cool. Taste and add more salt and pepper if needed

While the filling cools, make the pastry. Place the flour, cheddar, poppy seeds and butter in a food processor with a pinch of salt. Process until the mixture resembles fine breadcrumbs. Add 60–80ml of chilled water and process until the mixture comes together to form a smooth ball. Wrap in cling film and chill for 30 minutes

Once rested, roll out the pastry on a lightly floured board into a 30cm disc and place on a lined baking tray

Mix all but a tablespoon of the eggs to the cooled leek and mushroom mix and then place into the centre of the pastry. Fold over the 5cm border and roughly pleat. Brush the pastry edge with the beaten egg and sprinkle liberally with Parmesan. Bake for 30-35 minutes, or until golden and cooked through

While the pie cooks, heat some olive oil in a frying pan and add the sage leaves, frying until crisp. When the pie is looking perfect take it out of the oven and top with the crispy sage